chapter 2 basic components of living systems

Question 1

what organelles are in animal cells?

Answer 1

cell membrane, cytoplasm, centrioles, RER, SER, golgi apparatus, lysosomes, mitochondria, nucleus, ribosomes.

Question 2

what organelles are in plant cells?

Answer 2

cell membrane, cell wall, cytoplasm, chloroplasts, RER, SER, golgi apparatus, mitochondria, nucleus, ribosomes, permanent vacuole, possibly lysosomes

Question 3

what organelles are in prokaryotic cells?

Answer 3

cell membrane, cell wall, cytoplasm, ribosomes, free floating DNA, plasmids

Question 4

what is the function of the cell membrane?

Answer 4

controls what enters and exits the cell (important for homeostasis)

Question 5

what is the function of the cell wall?

Answer 5

important for cell structure and shape also provides additional protection

Question 6

what is the function of the cytoplasm?

Answer 6

site of chemical reactions, has cytosol (jelly) and cytoskeleton supporting organelles.

Question 7

what is the function of the centrioles?

Answer 7

come from the centrosome, involved with cell division and spindle fibres. positions flagella and cilia.

Question 8

what is the function of chloroplasts?

Answer 8

involved in photosynthesis

Question 9

what is the structure and function of the SER/RER?

Answer 9

has many folds, helps materials get around cell and processes molecules.
RER- has ribosomes to make proteins
SER- makes lipids/steroids and involved in detoxification

Question 10

what is the function of the golgi apparatus?

Answer 10

assembles items sent from ER, modifies, sorts and packages materials for delivery

Question 11

what is the function of the lysosome?

Answer 11

contains enzymes to break down and digest substances

Question 12

what is the function of the mitochondria?

Answer 12

makes ATP, is the cellular respiration site.

Question 13

what is function of the nucleus?

Answer 13

contains genetic material, controls cell activities

Question 14

what is the function of ribosomes?

Answer 14

makes proteins

Question 15

what is the function of vacuoles?

Answer 15

stores material depending on cell type

Question 16

what are the 3 components of the cytoskeleton?

Answer 16

microtubules(tubulin), microfilaments (actin), intermediate filaments

Question 17

what parts of the cytoskeleton are found in eukaryotes and prokaryotes?

Answer 17

eukaryotic- all 3
prokaryotic- microtubule, microfilaments

Question 18

what is the functions of the cytoskeleton?

Answer 18

helps keep cell’s shape, can actively contract allowing cells to migrate, allow organelles to move around inside the cell, cell division (spindle fibres)

Question 19

how many lenses does a compound light microscope have?

Answer 19

2

Question 20

what are the different types of slide preparation?

Answer 20

dry mount, wet mount, squash slides, smear slides

Question 21

what is a wet mount?

Answer 21

specimens suspended in liquid and a cover slip is placed on top.

Question 22

what is a dry mount?

Answer 22

solid specimens are cut into thin pieces and a cover slip is placed on top

Question 23

what is a squash slide?

Answer 23

wet mount is prepared then a slide is used to gently press down the cover slip to squash the specimen

Question 24

what is a smear slide?

Answer 24

edge of a slide is used to smear the specimen onto another slide

Question 25

Why are stains used when viewing cells under a microscope?

Answer 25

many cell structures are transparent so stains increase contrast which allows organelles to become more visible

Question 26

What do crystal violet and methylene blue do?

Answer 26

they are positively charged dyes so attract the negatively charged cytoplasm leading to staining of organelles

Question 27

what do nigrosin and congo red do?

Answer 27

they are negatively charged dyes and are repelled by negatively charged cytosol therefore staining the outside of the cells leaving the cells unstained making them more visible.

Question 28

what is the calculation for magnification?

Answer 28

size of image/actual size

Question 29

what is the limiting factor in light microscopy?

Answer 29

resolution and lenses increase magnification but it will become too blurred at a point

Question 30

How do TEMs work?

Answer 30

a beam of electrons is transmitted through a specimen and focused to produce an image

Question 31

what is the resolution of a TEM?

Answer 31

~0.5nm

Question 32

how does an SEM work? what images does it produce?

Answer 32

beam of electrons are sent across the surface of the specimen and reflected electrons are collected. it produces 3D surface images of the specimen

Question 33

what is the resolution of an SEM?

Answer 33

3-10nm

Question 34

Give an advantage and a disadvantage of light microscopes.

Answer 34

easy to operate and cheaper, images produced in colour. only up to 2000x magnification, 200nm resolution

Question 35

Give an advantage and a disadvantage of electron microscopes.

Answer 35

500,000x magnification, very high resolution. vacuum is required and very expensive/hard to operate

Question 36

what is an artifact?

Answer 36

visible structural detail caused by processing the specimen rather than being a feature of a specimen

Question 37

what is a laser scanning confocal microscope? and where is it used?

Answer 37

a microscope that employs a laser beam and a pin hole aperture to produce an image with very high resolution. it is used to diagnose eye diseases

Question 38

what are atomic force microscopes?

Answer 38

type of scanning microscope that uses a mechanical probe to ‘feel’ a specimen’s surface. resolution of 0.1nm

Question 39

what is the structure of the nucleus?

Answer 39

It has a double membrane called a nuclear envelope which surrounds DNA protecting it. Nuclear pores are present to allow molecules to move in and out of the nucleus.

Question 40

what is the function of the nucleolus?

Answer 40

area within the nucleus responsible for producing ribosomes

Question 41

what are flagella and cilia?

Answer 41

flagella is an extension used to enable cell mobility and sometimes detects chemical changes in the cell’s environment. cilia are important in sensory organs like the nose. each cilium contains 2 central microtubules surrounded by 9 other microtubules referred to as the 9+2 arrangement

Question 42

explain how proteins are synthesised and produced.

Answer 42

•the nucleolus forms ribosomes which can be free floating or attached to the RER. •proteins are synthesised on ribosomes bound to the RER •they then pass into the cisternae of the RER and are packaged into vesicles •these vesicles travel to the golgi apparatus along the cytoskeleton •they fuse with the cis face of the golgi body and proteins enter •proteins are structurally modified and packaged into vesicles and leave via the trans face •secretory vesicles travel to the cell membrane and fuse with it releasing their contents via exocytosis •some vesicles form lysosomes containing enzymes used in the cell.